Morphological study on the inferior olivary nuclear complex of the donkey (Equus asinus)

This study provides basic data on the normal structure of the inferior olivary complex (IOC) of the donkey, Equus asinus, at the light microscopic level. In common with that of other mammals, the donkey IOC consisted of three major nuclei and four minor groups of cells. The former was comprised of the medial and dorsal accessory olives (MAO and DAO, respectively) and the principal olive (PO), and the latter was comprised of the dorsal cap, nucleus beta, ventrolateral outgrowth and dorsomedial cell column. The MAO had the longest rostral to caudal representation and formed the caudal pole of IOC. The DAO was located dorsally to the MAO in the caudal half of the IOC. In the rostral half, the DAO bended ventrally and merged with the dorsal lamella of PO. More rostrally, the DAO lost its connection with the dorsal lamella and then conversely connected with the ventral lamella of PO. The DAO formed the rostral pole of the IOC. The PO extended through the rostral half of the IOC. The dorsal cap was a small group of cells. Overall, the donkey IOC is similar to that of other mammals.     

Olivary projections from the pretectal region in the cat studied with horseradish peroxidase and tritiated amino acids axonal transport

The organization of the projection from the pretectal region to the inferior olive in the cat was studied with autoradiographic and horseradish peroxidase (HRP) methods. After injections of HRP into the olive in six cats, cells were labeled ipsilaterally in the anterior pretectal nucleus (NPA), the posterior pretectal nucleus (NPP), the nucleus of the optic tract (NOT), and the dorsal terminal nucleus of the accessory optic tract (DTN). In three experiments, tritiated amino acids were injected into those parts of the pretectal region which contained labeled cells in the HRP experiments, and the projections to the olive were plotted. Both NPA and NPP projected to the rostral half of the dorsal accessory olive, the rostromedial margin of the ventral lamella, and the lateral part of the ventrolateral outgrowth. NOT projected to the caudal half of the dorsal cap, while DTN projected to both the dorsal cap and nucleus beta. The projections are entirely ipsilateral.     

Presence of catecholamine-related enzymes in a subpopulation of primary sensory neurons in dorsal root ganglia of the rat.

The presence of enzymes (tyrosine hydroxylase (TH) and dopamine-beta-hydroxylase (D beta H)) and enzymatic activities (monoamino oxidase, (MAO)) related to catecholamine synthesis and degradation have been investigated in cervical, thoracic and lumbar dorsal root ganglia (DRG) of adult male rats using immunohistochemical and enzyme histochemical techniques, respectively. A small population (between 2-4%) of TH-like immunoreactive and MAO positive neurons was found. They were small in diameter (18 +/- 2 microns), predominate in lumbar DRG and did not display D beta H-like immunoreactivity. These sensory neurons which are likely catecholaminergic were insensitive to systemic administration of capsaicin and 6-hydroxydopamine. Colchicine administration caused an increase of TH-like immunoreactivity and MAO activity. Pargyline produced an increase in TH-like immunoreactivity and the disappearance of MAO activity. The possible dopaminergic nature of the subpopulation of DRG sensory neurons investigated in the present study is discussed.     

Topographic organization of the karyometric response to neonatal castration of the male mouse in the paraventricular and ventromedial hypothalamic nuclei

We have analysed the karyometric development of four topographic subdivisions of the paraventricular nucleus (rostral, medial, lateral and caudal) and three topographic subdivisions of the ventromedial nucleus (ventral, central and dorsal) of the hypothalamus in neonatally castrated male mice. Castration at birth produces a decrease of the nuclear sizes from the 10th to the 35th postnatal day, but after this age, no differences were detected in comparison with the sizes of the control male mice. Neonatal gonadal hormone deprivation also produces changes in the nuclear shape of the nuclei, that tend to be more spherical in both centres, as we could establish after the study of the form factor parameter (perimeter/area ratio). We have found differences in the response of both hypothalamic nuclei to neonatal castration and differences in the response of the topographic subdivisions of both of them.     

Efferent connections of the striatum in Tupinambis nigropunctatus

The striatum of the lizard Tupinambis nigropunctatus lies in the lateral wall of the telencephalon and consists of two major subdivisions: the dorsal striatum and the ventral striatum. Electrolytic lesions were placed in all parts of the striatal complex and in adjacent areas and the subsequent anterograde degeneration was studied using the Nauta-Gygax and Fink-Heimer techniques. Lesions in the dorsal striatum cause terminal degeneration in the ventral striatum both ipsi- and contralaterally. In addition, projections have been found to the lateral amygdaloid nucleus and to parts of the dorsal striatum not affected by the lesion. Following lesions in the ventral striatum fiber degeneration could always be observed in the ventral peduncle of the lateral forebrain bundle. Corresponding terminal degeneration was found in the anterior and posterior entopeduncular nuclei, the tegmentum mesencephali, the substantia nigra, the prerubral area, the mesencephalic central grey and the lateral cerebellar nucleus. When the large celled part of the ventral striatum was involved in the lesion additional degeneration could be traced to the nucleus rotundus via the dorsal peduncle of the lateral forebrain bundle.     

Selective Increase in Dopamine Utilization in the Shell Subdivision of the Nucleus Accumbens by the Benzodiazepine Inverse Agonist FG 7142

Abstract: We examined the effects of the benzodiazepine inverse agonist FG 7142 on dopamine metabolism in the core and shell subdivisions of the nucleus accumbens. FG 7142 (15 mg/kg i.p.) or vehicle was administered to adult male rats 30 min before they were killed. Selected brain regions, including samples from the whole nucleus accumbens as well as core and shell subdivisions, were collected and assayed for tissue concentrations of dopamine and its major metabolite, 3,4-dihydroxyphenylacetic acid. Consistent with previous reports, FG 7142 administration increased dopamine utilization in the medial prefrontal cortex but not the whole nucleus accumbens. Examination of subdivisions revealed that FG 7142 produced increased dopamine utilization in the shell subdivision of the nucleus accumbens. No effect of FG 7142 on dopamine utilization in the core region of the nucleus accumbens was observed. These data are discussed in terms of in vivo microdialysis studies reporting increased dopamine release in the nucleus accumbens after FG 7142 administration.     

The beta sector of the rabbit's dorsal lateral geniculate nucleus

The beta sector of the rabbit's dorsal lateral geniculate nucleus is a small region of nerve cells scattered among the fibres of the geniculocortical pathway. In its topographical relations it resembles the perigeniculate nucleus of carnivores, which contains neurons driven by geniculate and visual cortical neurons and which sends inhibitory fibres back into the geniculate relay. We have traced retinogeniculate, geniculocortical and corticogeniculate pathways in rabbits by using horseradish peroxidase or radioactively labelled proline and have found that the beta sector resembles the perigeniculate nucleus in receiving no direct retinal afferents, sending no efferents to the visual cortex (V-I), and receiving afferents from the visual cortex. The corticogeniculate afferents are organized so that the visual field map in the beta sector and the main part of the lateral geniculate relays are aligned, as are the maps in the cat's perigeniculate nucleus and the main part of the geniculate relay of carnivores. Electron microscopical studies show similar types of axon terminals in the rabbit and the cat for the main part of the geniculate relay on the one hand and for the beta sector and the perigeniculate nucleus on the other. Earlier observations that the proportion of putative inhibitory terminals (F-type terminals) is lower in the rabbit's than the cat's geniculate region are confirmed. A major difference between the beta sector and the perigeniculate nucleus has been revealed by immunohistochemical staining for GABA. Whereas almost all of the cat's perigeniculate cells appear to be GABAergic, the proportion in the beta sector is much lower, and not significantly different from that found in the main part of the rabbit's geniculate relay. It is concluded that the beta sector shares many of the organizational features of the perigeniculate nucleus. A common developmental origin seems probable, but the functional differences remain to be explored.     

Peptide immunoreactive neurons in the amygdala and the bed nucleus of the stria terminalis project to the midbrain central gray in the rat.

The central nucleus of the amygdala, bed nucleus of the stria terminalis, and central gray are important components of the neural circuitry responsible for autonomic and behavioral responses to threatening or stressful stimuli. Neurons of the amygdala and bed nucleus of the stria terminalis that project to the midbrain central gray were tested for the presence of peptide immunoreactivity. To accomplish this aim, a combined immunohistochemical and retrograde tracing technique was used. Maximal retrograde labeling was observed in the amygdala and bed nucleus of the stria terminalis after injections of retrograde tracer into the caudal ventrolateral midbrain central gray. The majority of the retrogradely labeled neurons in the amygdala were located in the medial central nucleus, although many neurons were also observed in the lateral subdivision of the central nucleus. Most of the retrogradely labeled neurons in the BST were located in the ventral and posterior lateral subdivisions, although cells were also observed in most other subdivisions. Retrogradely labeled neurotensin, corticotropin releasing factor (CRF), and somatostatin neurons were mainly observed in the lateral central nucleus and the dorsal lateral BST. Retrogradely labeled substance P-immunoreactive cells were found in the medial central nucleus and the posterior and ventral lateral BST. Enkephalin-immunoreactive retrogradely labeled cells were not observed in the amygdala or bed nucleus of the stria terminalis. A few cells in the hypothalamus (paraventricular and lateral hypothalamic nuclei) that project to the central gray also contained CRF and neurotensin immunoreactivity. The results suggest the amygdala and the bed nucleus of the stria terminalis are a major forebrain source of CRF, neurotensin, somatostatin, and substance P terminals in the midbrain central gray.     

The cochlear nuclei in man.

The human cochlear nuclei are composed of a ventral and a dorsal nucleus which are similar, though not identical, in their cytoarchitecture to those of other mammals. The ventral cochlear nucleus (VCN) consists of a rostral area of spherical cells, a central area of multipolar and globular cells, a posterior area of octopus cells, and laterodorsal cap of small neurons. The interareal boundaries are less distinct in man than in the cat. The central region of multipolar cells and the cap area of small cells constitute the bulk of the human VCN. The spherical, globular, and octopus cells appear relatively less numerous in man than in other mammals. The dorsal cochlear nucleus (DCN) in man is relatively large, but lacks the typical stratification seen in other mammals, with only vestiges of the granular and molecular layers remaining. Virtually the entire DCN consists of an area of cochlear fiber neuropil containing pyramidal cells, small neurons, and occasional giant cells. The pyramidal cells have lost their typical radial orientation and lie scattered within the cochlear neuropil. Thus the entire human DCN may be equivalent to layers 2 and 3 of this nucleus in other mammals. In spite of the relatively large DCN, the acoustic striae appear small. This is in contrast to the large trapezoid body leaving the VCN. Intrinsic and descending fiber pathways to the cochlear nuclei are not clearly defined and may be less prominent in man than in the cat.     

Subcellular localization of RNAs in transfected cells: role of sequences at the 5' terminus

We have investigated the intracellular location of RNAs transcribed from transfected DNA. COS cells transfected with a clone containing the human adult beta globin gene contain three classes of globin RNAs. Their 3' termini and splice sites are indistinguishable from those of mature reticulocyte beta globin mRNA, and they are polyadenylated. However, as determined by S1 mapping, their 5' sequences are different. The 5' terminus of one is the same as that of mature beta globin mRNA (+1, cap site). The presumed 5' terminus of the second is located 30 nucleotides downstream from the cap site (+30). The third class contains additional nucleotides transcribed from sequences located 5' to the cap site (5' upstream RNA). The 5' upstream RNA molecules are restricted to the nucleus and are more stable than heterogeneous nuclear RNA. The +30 and +1 RNAs are located primarily in the cytoplasm. The data support the notion that nucleotide sequences and/or secondary modifications in the 5' region determine if an RNA is to be transported.     

Acute Impact of Selected Pyridoindole Derivatives on Fos Expression in Different Structures of the Rat Brain

The impacts of three pyridoindole derivatives (PDs), designated as PD144, PD143, and PD104, which have previously been shown to have antidepressant (PD144) and anxiolytic (PD143, PD104) properties, were investigated on the Fos expressions in 11 different rat brain areas, including the medial prefrontal cortex, striatum, septum, accumbens nucleus (shell, core), bed nucleus of the stria terminalis, hypothalamic paraventricular nucleus, central amygdala, locus coeruleus, dorsal raphe nucleus, and the solitary tract nucleus. Control rats received vehicle, while the other three groups the PDs in a dose of 25 mg/kg/b.w. The animals were transcardially perfused with a fixative 90 min after the treatments. Coronal sections of 40-µm thickness were processed for Fos-immunostaining by avidin–biotin-peroxidase complex and visualized by nickel-intensified diaminobenzidine complex. Fos-labeled sections were counterstained with neuropeptides including corticoliberine (CRH), oxytocin (OXY), vasopressin (AVP), and vasoactive intestinal polypeptide (VIP) and processed for immunofluorescence staining using Alexa Fluor 555 dye. In all the three groups of animals, the upregulation of PDs-induced Fos expression only in 2 of 11 brain areas was investigated, namely, in the hypothalamic paraventricular nucleus (PVN) and the central amygdaloid nucleus (CeA). The other brain structures studied were devoid of Fos expression. Counterstaining of the Fos-labeled CeA-containing sections with VIP antibody revealed that the Fos expression stimulated by the PDs was upregulated in all the CeA subdivisions (lateral, ventral, capsular), except the medial one. Dual immunoprocessings showed Fos/CRH-labeling in both the PVN and the amygdala and Fos/OXY in the PVN. No Fos/AVP colocalizations were seen in the PVN. The obtained data provide the first view on the intracerebral effects of three new PDs derivatives, which effects were restricted only to the PVN and CeA areas. The present data may help to improve our understanding of the impact of the selected PDs on the brain and to anticipate possible behavioral and neuroendocrine consequences.     

Cytoarchitectonic study of the brain of a perciform species, the sea bass (Dicentrarchus labrax). II. The diencephalon

The cytoarchitecture of nuclei in the preoptic area, ventral thalamus, dorsal thalamus, epithalamus, hypothalamus, posterior tuberculum, synencephalon, and pretectum and the accessory optic nuclei was analyzed in a perciform teleost, the sea bass Dicentrarchus labrax, by using serial sections stained with cresyl-violet. In general, the cytoarchitecture of the preoptic area, ventral and dorsal thalamus, epithalamus, and synencephalon resembles the histological pattern of other teleosts. However, the parvocellular preoptic nucleus of sea bass has been subdivided into parvocellular and anteroventral parts for morphological and functional reasons. The hypothalamus of the sea bass seems to differ slightly from that of other teleosts. An elaborated lateral tuberal nucleus, with five subdivisions, and three different nuclei around the lateral recesses were recognized. A medial nucleus of the inferior lobe, which has been reported previously in the perciform Sparus aurata, is also present in the hypothalamus of sea bass but has not been described before in another advanced teleost. The organization of the pretectum and the accessory optic system is essentially similar in sea bass to that described in other perciforms with highly developed vision. The migrated portion of the posterior tuberculum of sea bass appears to differ from this region of the diencephalon in other teleosts. In sea bass, three cell masses that have been described previously only in the perciform Sparus aurata have been assigned to the migrated area of the posterior tuberculum. This study will provide the neuroanatomical basis for future morpho-functional studies to be done in the sea bass brain.     

Neural organization and responses to complex stimuli in the dorsal cochlear nucleus.

The dorsal division of the cochlear nucleus (DCN) is the most complex of its subdivisions in terms of both anatomical organization and physiological response types. Hypotheses about the functional role of the DCN in hearing are as yet primitive, in part because the organizational complexity of the DCN has made development of a comprehensive and predictive model of its input-output processing difficult. The responses of DCN cells to complex stimuli, especially filtered noise, are interesting because they demonstrate properties that cannot be predicted, without further assumptions, from responses to narrow band stimuli, such as tones. In this paper, we discuss the functional organization of the DCN, i.e. the morphological organization of synaptic connections within the nucleus and the nature of synaptic interactions between its cells. We then discuss the responses of DCN principal cells to filtered noise stimuli that model the spectral sound localization cues produced by the pinna. These data imply that the DCN plays a role in interpreting sound localization cues; supporting evidence for such a role is discussed.     

Intramedullary projections of the rostral nucleus of the solitary tract in the rat: gustatory influences on autonomic output

The efferent connections of the rostral nucleus of the solitary tract (NTS) in the rat were studied by anterograde transport of Phaseolus vulgaris leucoagglutinin. Rostral to the injection site, fibers travel through the rostral parvocellular reticular formation and deflect medially or laterally around the motor trigeminal nucleus, giving off few terminals in these nuclei and terminate in the parabrachial nucleus. Moderate projections to the peritrigeminal zone, including the intertrigeminal nucleus and the dorsal subcoeruleus nucleus, were observed. Caudally to the injection site, dense innervations from the rostral nucleus of the solitary tract were detected in the parvocellular reticular formation ventral and caudal to the injection site and in the intermediate and ventral medullary reticular formation. The rostral central and ventral subdivisions of the NTS up to the level where the nucleus of the solitary tract abuts the fourth ventricle and the hypoglossal nucleus, receive moderate input from the rostral nucleus of the solitary tract. In general, the projections from the rostral nucleus of the solitary tract were bilateral with an ipsilateral predominance. The caudal part of the nucleus of the solitary tract, the dorsal motor nucleus of the vagus and the facial nucleus were not labeled. It is concluded that medullary rNTS projections participate in oral motor behavior and autonomic control of abdominal organs.     

The assembly and function of perinuclear actin cap in migrating cells

Stress fibers are actin bundles encompassing actin filaments, actin-crosslinking, and actin-associated proteins that represent the major contractile system in the cell. Different types of stress fibers assemble in adherent cells, and they are central to diverse cellular processes including establishment of the cell shape, morphogenesis, cell polarization, and migration. Stress fibers display specific cellular organization and localization, with ventral fibers present at the basal side, and dorsal fibers and transverse actin arcs rising at the cell front from the ventral to the dorsal side and toward the nucleus. Perinuclear actin cap fibers are a specific subtype of stress fibers that rise from the leading edge above the nucleus and terminate at the cell rear forming a dome-like structure. Perinuclear actin cap fibers are fixed at three points: both ends are anchored in focal adhesions, while the central part is physically attached to the nucleus and nuclear lamina through the linker of nucleoskeleton and cytoskeleton (LINC) complex. Here, we discuss recent work that provides new insights into the mechanism of assembly and the function of these actin stress fibers that directly link extracellular matrix and focal adhesions with the nuclear envelope.     

Fluorinated phenylcyclopropylamines. Part 5: Effects of electron-withdrawing or -donating aryl substituents on the inhibition of monoamine oxidases A and B by 2-aryl-2-fluoro-cyclopropylamines

A series of racemic, diastereoisomeric aryl cyclopropylamines substituted with fluorine in the 2-position and electron-donating and electron-withdrawing groups on the aromatic ring have been prepared. These represent analogues of the classic MAO inhibitor tranylcypromine (trans-2-phenylcyclopropylamine, 1). Their activities as inhibitors of recombinant human liver monoamine oxidases A (MAO A) and B (MAO B) were determined. The trans-compounds were low micromolar inhibitors of both MAO A and MAO B with moderate MAO A selectivity while the less active cis-analogues were MAO B selective. In the trans-series, electron-withdrawing para-substituents increased the potency of MAO A inhibition while electron-donating groups such as methyl or methoxy had no influence on this activity. In contrast, aromatic ring substitution in the trans-series had essentially no effect on the inhibition of MAO B. The corresponding cis-compounds were shown to be 10-100 times less active against MAO A, while trans- and cis-compounds were quite similar in terms of inhibition of MAO B. The best MAO A/MAO B selectivity (7:1) in the trans-series was found for trans-2-fluoro-2-(para-trifluoromethylphenyl)cyclopropylamine (7d), while a 1:27 selectivity was found for cis-2-fluoro-2-(para-fluorophenyl)cyclopropylamine (10c). These results are discussed in connection with the pK(a) and logD values, the mechanism of action of tranylcypromines, and the geometry of the active site of the enzymes.     

Projections from neurons of the medial terminal nucleus of the accessory optic tract to the caudate nucleus in the cat revealed by combining techniques of retrograde axonal transport and experimentally induced degeneration

Neurons of the medial terminal nucleus of the accessory optic tract receiving direct retinal inputs were shown to project to the heat and body of the caudate nucleus in the cat using techniques of retrograde horseradish peroxidase axonal transport and experimentally induced degeneration. These primarily ipsilateral projections are evenly distributed throughout the aforementioned areas of the nucleus. Neurons of the medial terminal nucleus forming synaptic connections with caudate nucleus cells are distinguished by their varied shapes and sizes, ranging from 20 × 10 to 37.5 × 18 µm and are located in both the ventral and dorsal subdivisions of the nucleus. The supposed functional significance of these projections for the regulation of muscle tonus tension is discussed.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 18, No. 2, pp. 214–219, March–April, 1986.     

Identification of a calcium binding protein highly localized to the cochlear nucleus

A protein, designated as protein 10 (MW = 29 kDa, pI = 5.3), was shown to be highly localized to the cochlear nuclei of guinea-pigs and rats by the use of two-dimensional gel electrophoresis. In gels from guinea-pig brain, this protein appeared greatest in amounts in the ventral cochlear nucleus and within the deep regions of the dorsal nucleus. Intermediate amounts of protein 10 were found in the lateral superior olivary nucleus and dorsal nucleus of the lateral lemniscus with lesser amounts in telencephalic brain regions. Finally, incubation of nitrocellulose blots in ⁴⁵Ca²⁺ revealed that protein 10 is a calcium binding protein.     

Histochemical studies of monoamine oxidase of the brain of rodents

Summary MAO of the brain was investigated histochemically in mice, rats, guinea pigs and rabbits. Fresh frozen sections were subjected to the tryptamine-tetrazolium method by Glenner, Burtner and Brown (1957).MAO activity of the brain of 4 animal species is generally similar with respect to its pattern of distribution. However, the intensity of enzyme action of the brain as a whole differs somewhat in animal species, being highest in guinea pigs, intermediate in rats and lowest in mice and rabbits. The enzyme action occurs mainly in the neuropil of the cerebral grey matter, while weak or negative activity is generally observed in the white matter excepting the tractus retroflexus of Meynert.The marked activity is encountered in the interpeduncular nucleus, locus coeruleus, area postrema, dorsal nucleus of the vagus nerve, hypothalamus, habenular nuclei and midline nuclear group of the thalamus, nucleus of the brachium conjunctivum, and central grey matter. The enzyme activity is weak or negative in the neocortex, striatum, mamillary body, thalamic nuclei (excepting the habenula and midline nuclear group), subthalamic nucleus, substantia nigra, red nucleus and nuclei of the somatic cranial nerves.The possible function and significance of MAO in the brain were discussed particularly by comparing the sites of this enzyme with those of succinic dehydrogenase and cytochrome oxidase, and the inverse relation between these enzymes was suggested.     

An analysis of the cyto- and myeloarchitectonic organization of trigeminal nucleus interpolaris in the rat

The cyto- and myeloarchitectonic organization of trigeminal nucleus interpolaris (Vi) was examined in the rat using correlated Nissl- and myelin-stained sections. The caudal boundary of Vi is marked by a spatial overlap with the rostral pole of the medullary dorsal horn (MDH), where there is a dorsal and medial displacement of the substantia gelatinosa (SG, lamina II) layer of MDH. This spatial displacement was further documented using cytochrome-oxidase-reacted sections through the periobex region (POR) of the medulla, where the relatively unstained SG contrasts sharply with the intensely stained Vi neuropil. The rostral boundary of Vi is characterized partly by a distinct overlap with the caudal pole of the dorsomedial region (DM) of trigeminal nucleus oralis (Vo), and partly by a more gradual transition with ventral and lateral regions of Vo. The presence of the distinct MDH-Vi overlap is discussed in terms of its impact on the widespread contention that Vi is involved in the processing of dental pain afferents in the POR. Six separate and distinct regions of rat Vi can be distinguished on the basis of differences in their overall cyto- and myeloarchitecture: (1) a ventrolateral parvocellular region (vlVipc), which occupies the ventrolateral caudal half of Vi; (2) a ventrolateral magnocellular region (vlVimc), which occupies a similar region in the rostral half of the nucleus; (3) a border region (brVi), interposed between the spinal trigeminal tract (SVT) and vlVipc and vlVimc; (4) a dorsolateral region (dlVi), which lies predominantly in the rostral two-thirds of Vi subjacent to the dorsal half of SVT; (5) a dorsal cap region (dcVi), occupying the dorsomedial aspect of the nucleus throughout its entire rostrocaudal extent; and (6) an intermediate region (irVi), which lies immediately ventral to dcVi within the concavity formed by the medial borders of vlVipc and vlVimc. It is proposed that these cyto- and myeloarchitecturally distinct regions of Vi may largely represent functionally distinct regions, based on reported differences in the organization of afferent and efferent projections within the nucleus.